1. Field of the Invention
The present invention relates to an improvement of a display device in a single lens reflex camera view finder, arranged so that various photographing information is displayed by means of a liquid crystal display member in the view finder of the camera.
2. Description of the Prior Art
Generally, a display device making use of liquid crystal comsumes little power and can be built economically in a small space, so that it has been widely used as the display for various kinds of the portable appliances (for example, time pieces, desk computer and so on). Further, quite recently, various kinds of information display devices for cameras have been proposed, whereby various photographing information is displayed in the finder view field frame by means of a display device making use of liquid crystal, instead of LED or the like. The reason is that in case the photographing information is displayed by means of liquid crystal in the finder view field frame of the camera, the power consumption can be reduced remarkably in comparison with display devices making use of LED, while the freedom of the display configuration can be widened. In this way, by means of of the liquid crystal display, it is possible to realize a display device suitable for the modern camera which is arranged so that much photographing information can be displayed along the finder view field frame.
However, quite different from an active display by means of LED or the like, a liquid crystal display is a passive display by means of penetrating or reflected light, so that without any illuminating light the display can not be visually recognized. Further, it is necessary that the construction of the liquid crystal display member itself, and the liquid crystal display device including the liquid crystal display member, should be dust-proof, so that many problems occur in the construction of the liquid crystal display device and the mounting of the liquid crystal display device on the view finder optics. Under such circumstances, the present invention is advantageous as will be explained later.
Generally, a display memebr making use of liquid crystal is constructed as is shown in FIGS. 1 and 2. The figures show glass base plates 1, 2 each having a transparent electrode pattern (not shown), and polarization plates 3, 4. The transparent electrode patterns are provided on the planes of the glass base plates 1, 2, whereby liquid crystal matter 6 is sandwiched with proper thickness between the plates. Further, the circumference or perimeter of the liquid crystal matter 6 is sealed by means of a seal portion 5 serving at the same time as a spacer. A display part 7 is arranged so that by applying a voltage between the glass base plates 1 and 2 the polarization angle of the liquid crystal is varied so as to produce a display pattern. In this kind of liquid crystal display member it is necessary to hold the liquid crystal matter 6, maintain the width of the seal portion larger than a certain determined value in order to protect the liquid crystal member itself, and shade the seal portion 5 in order to obtain a clear display pattern from the light. For this reason, in the conventional liquid crystal display device in which the above mentioned liquid crystal display member is built in the finder view field frame without accomodating the width of the seal portion 5, the finder view field frame is too distant from the display part of the liquid crystal display member to obtain a clear display of various photographing information and a high view field ratio of the finder.